1 files changed, 79 insertions, 0 deletions
diff --git a/layout/style/nsStyleStructFwd.h b/layout/style/nsStyleStructFwd.h
new file mode 100644
index 0000000000..5187a764b9
--- /dev/null
+++ b/layout/style/nsStyleStructFwd.h
@@ -0,0 +1,79 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Forward declarations to avoid including all of nsStyleStruct.h.
+ */
+
+#ifndef nsStyleStructFwd_h_
+#define nsStyleStructFwd_h_
+
+namespace mozilla {
+
+enum class StyleStructID : uint32_t {
+/*
+ * Define the constants eStyleStruct_Font, etc.
+ *
+ * The C++ standard, section 7.2, guarantees that enums begin with 0 and
+ * increase by 1.
+ *
+ * Note that we rely on the inherited structs being before the rest in
+ * ComputedStyle.
+ */
+#define STYLE_STRUCT_INHERITED(name) name,
+#define STYLE_STRUCT_RESET(name)
+#include "nsStyleStructList.h"
+#undef STYLE_STRUCT_INHERITED
+#undef STYLE_STRUCT_RESET
+
+#define STYLE_STRUCT_RESET(name) name,
+#define STYLE_STRUCT_INHERITED(name)
+#include "nsStyleStructList.h"
+#undef STYLE_STRUCT_INHERITED
+#undef STYLE_STRUCT_RESET
+};
+
+struct StyleStructConstants {
+  static const uint32_t kStyleStructCount =
+#define STYLE_STRUCT_RESET(name) 1 +
+#define STYLE_STRUCT_INHERITED(name) 1 +
+#include "nsStyleStructList.h"
+#undef STYLE_STRUCT_INHERITED
+#undef STYLE_STRUCT_RESET
+      0;
+
+  static const uint32_t kInheritedStyleStructCount =
+#define STYLE_STRUCT_RESET(name)
+#define STYLE_STRUCT_INHERITED(name) 1 +
+#include "nsStyleStructList.h"
+#undef STYLE_STRUCT_INHERITED
+#undef STYLE_STRUCT_RESET
+      0;
+
+  static const uint32_t kResetStyleStructCount =
+#define STYLE_STRUCT_RESET(name) 1 +
+#define STYLE_STRUCT_INHERITED(name)
+#include "nsStyleStructList.h"
+#undef STYLE_STRUCT_INHERITED
+#undef STYLE_STRUCT_RESET
+      0;
+
+  static_assert(kStyleStructCount <= 32, "Bitmasks must be bigger!");
+
+  static const uint32_t kAllStructsMask = (1 << kStyleStructCount) - 1;
+  static const uint32_t kInheritedStructsMask =
+      (1 << kInheritedStyleStructCount) - 1;
+  static const uint32_t kResetStructsMask =
+      kAllStructsMask & (~kInheritedStructsMask);
+
+  static uint32_t BitFor(StyleStructID aID) {
+    return 1 << static_cast<uint32_t>(aID);
+  }
+};
+
+}  // namespace mozilla
+
+#endif /* nsStyleStructFwd_h_ */